Ball separating means for ball rolling machines



Aug. 6, 957 H. w. GRONEMEYER 2,801,457

BALL SEPARATING MEANS FOR BALL ROLLING MACHINES Filed Nov. 5, 1951 5 Sheets-Sheet 1 INVENTOR. HERBERT W. GRONEMEYER A TTORNE Y ,Aug. 6 1957 HLW. GROl NEMEYER 2,801,457

BALL SEPARATING MEANS FOR- BALL. ROLL-INC MACHINES Filed Nov. 5, 1951 5 Sheets-Sheet 2 IN VEN TOR. HERBERT W GRONETMEYER A T TORNE Y 1957 H. w. GRONEMEYER' 2,801,457

BALL SEPARATING MEANS FOR BALL. ROLLING MACHINES 5 Sheets-Sheet 3 Filed Nov.

, INVENTOR. HERBERT- W GRONEME'YER ATTORNEY BALL SEPARATING MEANS FQR BALL ROLLING MACHINES Herbert W. Gronemeyer, Kansas City, Mo., assignor, by mesne assignments, to Armco SteelCorperatic-n, a cor poration of Ohio Application November 5, 1951, Serial No. 254,906

11 Claims. (Cl. 2966) My invention relates to ball forming machines, and more particularly to ball separating means for ball rolling machines.

My improved ball separating means comprises a plurality of twisting rolls and means for feeding connected ball formations to said twisting rolls. It has been found that where twisting means is utilized for separating one ball formation from another of a string of connected ball formations, comprising alternating ball formations and narrow neck portions connecting the same, the tendency is for the entire string of connected ball formations to twist substantially on the axis of said connected string. It has also been found that it is necessary to positively feed the connected ball formations into the separating means, as the separating means, even when of a character that would apparently tend to move the ball formations lengthwise of the connected series, will not do this satisfactorily.

It is absolutely necessary that the ball formations be fed into the twisting mechanism accurately so as to prevent any damage or destruction of the various ball formations by means of the twisting device. This is particularly true where the twisting means comprises a plurality of twisting rolls that are spirally grooved to receive the ball formations and twist the same oif.

One of the principal difficulties encountered in connection with twisting one ball formation at a time off from the string or series of connected ball formations has been that unless all of the ball formations that are not in the twisting means are held against rotation about an axis running generally lengthwise of the connected string of ball formations, it is impossible to separate each ball formation from the others as it is acted on by the twisting mechanism. In order that this can be accomplished 'it is necessary to have holding means closely adjacent the twisting means and this holding means has to act on a ball formation that is connected with onein the twisting mechanism by a narrow neck portion, so that the connected ball formation will be acted on by the twisting means to twist the same around relative to the held ball formation.

While it is desirable and necessary to hold the ball formation next adjacent the one that has just entered the twisting mechanism to assure the separation of each ball formation from all the others as the separating means acts thereon, it has been found that the ball formations are damaged by being marred or cut into by some of the moving parts unless positive feed of the connected ball formation into the twisting mechanism is accomplished, and the ball formation that is not yet in engagement with the twisting mechanism, but is the next to enter the same, is held against rotation.

-t is the principal purpose of my invention to provide ball separating means comprising a plurality of twisting rolls that are spirally grooved and which rotate about parallel axes, said rolls preferably comprising a pair of rolls that rotate about fixed axes and a roll cooperating therewith that is urged toward said pair of rolls yieldnited States Patent ice from the other pair of rolls to thus prevent undue damage to'the ball formations by improper engagement with the twisting rolls, and to provide means in cooperation with such rolls that will positively feed and at the same time prevent rotation of the ball formations that are out of engagement with the twisting rolls so that the same will be'positively fed into said twisting rolls and will not'rotate until after engagement with said twisting rolls.

'It is another important purpose of my invention to provide means for feeding connected ball formations to'twisting rolls, or similar twisting mechanism, comprising a plurality of rollers that are arranged in rows in close adjacency so that a plurality of feed rollers will be engaging the connected ball formations that are being fed to said rollers operate about axes that are substantially perpendicuiar to or transverse to the direction of feed of the connected ball formations and are of such a character,

preferably being cylindrical, that these will hold the connected ball formations from rotation.

While such an arrangement of two rows of rollers arranged so that the rollers are in series that are opposite each other for engagement with the connected ball formations will positively feed the connected ball formations to and into the twisting mechanism, it is necessary that the pair of feed rollers that is the nearest the twisting mechanism be in engagement with the ball formation that is connected by means of a narrow neck portion, with the ball formation that is ahead of the same and .in engagement with the twisting mechanism. In order to accomplish this the rollers are, preferably, of a diameter that is at least no more than, and preferably less than that of the balls, with a pair thereof closely adjacent the twisting rolls, and in order that a firm holding action be exerted on the ball formations, both to obtain the necessary frictional grip thereon to feed the same toward the twisting mechanism and to prevent rotation or twisting of the ball formations between said feed rollers, means is provided for yieldingly individually urging the rollers of each of the rows toward the other row.

It is a further purpose of my invention to provide a twisting mechanism comprising a plurality of spirally grooved rolls, all rotating about parallel axes, and a pair thereof about fixed axes, and a third roll yieldingly mounted so as to be urged toward the cooperating paired rolls, to thus prevent any possibility of disengagement of the ball formations by the rolls, but permitting movement of the yieldingly mounted twisting roll away from the others in case the ball formations do not feed properly into the rolls so that the same might be damaged thereby, or in case a malformed ball formation or other obstacle enters between the rolls which might damage the same. In order to obtain this yielding mounting of the third roll, it is preferably mounted on an arm that is pivotally mounted on the axis of rotation of one of the rolls that rotates about a fixed axis, and has driving means for positively driving the same in the same direction as the other two rolls from acomm onsource, said driving means including driving means mounted on said arm and movable therewith so that the driving means will be continuously in mesh and the yieldingly mounted roll will be continuously rotating, whether it is in cooperative relation with the paired rolls that are mounted on fixed axes or moved out of said cooperative positon. In order to obtain the yielding action, resilient means is provided for holding the pivotally mounted arm in a position so that it will cooperate with the other two pairs of rolls, a stop member being provided to limit movement of said yieldingly mounted roll toward the other rolls under the urging of said resilient means, said stops means being adjustable to adjust the spacing of the rolls relative to each other.

It is another purpose of my invention to provide driving means for the feed rollers that rotate all said feed rollers positively at the same rate, said driving means being preferably so mounted as to be remote from the portions of the rollers in engagement with the connected string or length of ball formations, and to drive said feed rollers from the same source as the twisting rolls so that the feed rollers will be co-ordinated in their feeding action with the necessary forward movement of the balls away from the connected string or length of balls during the engagement thereof with the spirally grooved twisting rolls.

Other objects and advantages of my invention will appearas the description of the drawings proceeds. I desire to have it understood, however, that I do not intend to limit myself to the particular details shown or described, except as defined by the claims.

In the drawings:

Fig. 1 is a side elevation, partly broken away, of my improved ball separating mechanism, the final pair of swaging rolls for forming the connected ball formations being shown diagrammatically.

Fig. 2 is a top plan view, partly broken away, of the ball separating means and the feed roller drive.

Fig. 3 is an end elevation of the twisting rolls and their mounting as viewed from the entrance end of said rolls.

Fig. 4 is a fragmentary side elevational view of the feed roller drive and mounting for the upper end of said feed rollers.

Fig. 5 is an elevational view, partly broken away, showing the lower ends of the feed rollers and associated parts, taken substantially on the line 55 of Fig. 1.

Fig. 6 is a fragmentary horizontal sectional view taken substantially on the line 66 of Fig. 5.

Fig. 7 is a diagrammatic view in the plan, showing the manner in which the feed rollers cooperate with the connected ball formations to feed the same to the twisting mechanism.

Fig. 8 is a vertical sectional view taken on the line 8-8 of Fig. 1, and

Fig. 9 is a vertical section taken substantially on the line 99 of Fig. 1.

Referring in detail to the drawings, my improved ball separating mechanism is applied to a ball forming machine that has a main drive shaft 10, which is driven from a suitable source by means of belts operating over a grooved pulley 11, said main drive shaft also driving the swaging rolls 12 through suitable gearing, including reduction gearing, not shown. Mounted on the main drive shaft is a pinion 13, which meshes with a. large idler gear 14 mounted on a suitable shaft carried by the frame 15. The gear 14 meshes with a gear 16 that is keyed on the shaft 17, suitable bearings being provided on the frame member for said shaft. A gear 19 is also keyed on said shaft and meshes with a gear 20 mounted on a stub shaft 40 mounted in the bearing block 41. The gear 19 meshes with the gear 21 keyed to the shaft 22, said shaft 22 being mounted in suitable bearings on the frame 15. The bearings for one end of the shafts 17 and 22 are provided by means of said bearing block 41 and cap members 18 and 23, respectively.

A spirally grooved twisting roll 24 is keyed on the shaft 17 and a spirally grooved twisting roll 25 is keyed on the shaft 22. Keyed on a shaft 26 is another spirally grooved twisting roll 27. The shaft 26 is mounted in suitable bearings provided on a lever 28, which is mounted to swing on pivot pins 29 mounted on a pair of upstanding brackets 30 on the frame 15, said lever 28 having a pair of pivot ears 31 thereon and said brackets having upstanding ears 32 through which said pivot pins extend to provide said pivotal mounting. The lever 28 has a wide thick body portion that is upwardly bowed at 33, as will be obvious from Fig. 3, said portion being provided with a suitable bearing for the shaft 26 formed therein and in a cap member 42. A bearing is provided for the shaft 17 by means of the bracket 30 and cap member 97, and for the shaft 22 by means of a bracket 98 and cap member 99. An arm 34 extends endwise from the member 28, the end portion 35 thereof being mounted between the legs 36 of a vertically elongated yoke-like member that has a transverse portion 37 and is mounted pivotally on a pivot member 38 mounted on the pivot block 39 on the base member 15.

The end portion of the arm 35 is provided with an opening that screw-threadedly receives the screw-threaded headed member 43, the head of said member 43 thus being adjustable relative to the end portion 35 of the arm 34. Mounted slidably in the transverse portion 37 of the yoke-like member 36 is a rod-like member 44, which is provided with a screw-threaded upper end 45 having a stop nut 46 and a lock nut 47 mounted thereon. The lower end portion of the rod-like member 44 is provided with a head 48 that has lateral extensions 49 providing for guided sliding movement of the head 48 on the arms 36 of the yoke-like member.

A screw-threaded portion 50 is also provided on the member 44, with which the stop nut 51 is screw-threadedly engaged, a compression coil spring 42 being mounted on the rod-like member 44 between the transverse portion 37 of the yoke-like member and said stop nut 51, thus providing for adjustment of the pressure exerted by the spring 52 tending to move the head 48 in a downward direction.

A post-like member 53 is mounted on the base 15 and is screw-threaded to a receive a screw-threaded headed member 54, which has the head 55 thereon, and which is provided with a nut 56 for locking the same in adjusted position on the post-like member 53. The member 43 is provided with a nut 57 engaging the lower screwthreaded end 58 thereof for locking the member 43 in adjusted position on the end portion 35 of the arm 34 with the head 59 thereof in such a position that it will be in engagement with the head 48, with the spring 52 under suflicient compression to hold said arm 34 in engagement with the head 55 of the stop member 54 when the twisting roll 27 is in proper cooperative relation with the rolls 24 and 25 that a ball formation of the connected series thereof will be in engagement with the spiral grooves in all of said rolls 24, 25 and 27 so as to be firmly held thereby so that said rolls will exert a twisting action on said ball formations in engagement with said grooves.

Should the ball formations not properly engage in the grooves in the members 24, 25 and 27, or should some foreign object or mal-formed projection on the connected ball formations enter between said rolls, the roll 27 will move upwardly as shown in dotted lines in Fig. 3 to compress the spring 52, the roll 27 thus yielding relative to the rolls 24 and 25 so that said rolls will not be damaged by any improper engagement of the connected ball formations therewith. Upon the connected ball formations again properly engaging in the spiral grooves in the rolls 24, 25 and 27, the spring 52 will return the arm 34 to position in engagement with the stop member 55 to the normal position shown in full lines in Fig. 3. The grooves in the rolls 24, 25 and 27 are designated by the numerals 60, 61 and 62, respectively. The rolls 24, 25

and 27 are alike, having the same shaped grooves thereing means both when in normal position and when out of such normal position to drive said roll 27 in the same direction and at the same rate of rotation as the rolls 24 and 25. A gear 63 is keyed on the shaft 17, said gear 63 being the same size as the gear 19 and meshing with an idler gear 64 mounted on the pivot pin 29 and meshing with a gear 65 keyed on the shaft 26. Thus the roll 27 will be rotated at the same speed as the rolls 24 and 25 and in the same direction, the gears 19, 21, 63 and 65 being all of the same size with the same number of teeth. I

Means is provided for holding the ball formation next to the one that has just entered between the rolls 24, 25

and 27, which is approaching said rolls, from rotation so that the ball formation being rotated by means of the rolls 24, 25 and 27 will be twisted off from the ball formation thus held. Said holding means also holds a plurality of ball formations between the means for forming the connected ball formations and the next one to enter the twisting rolls against rotation. Said means comprises a plurality of rollers 66 of relatively small diameter and great length, which are arranged in two longitudinal rows so as to be in oppositely arranged pairs. Said rollers extend through openings in a plate-like member 67, which is provided on an upstanding portion 95 on the frame having transverse shelf-like portions 96, upon which said plate-like member 67 is mounted, said rollers having ring-like members 68 mounted in suitable grooves therein that serve as bearing members engaging the platelike member 67 and having reduced end portions 69, on which the gears 70 are keyed, there being a gear 71 for each of said rollers, said gears 70 being thus arranged in rows co-axial with the upper ends of the rollers 66.

The gears 70 are driven by means of a large gear 71,

which is keyed on a shaft 72 mounted in hearings on an upstanding bracket 73 provided on the frame of the machine, and to which is keyed a sprocket 74, over which the sprocket chain 75 operates, said sprocket chain being driven from a sprocket, not shown, that is mounted to rotate with one of the ball forming rolls. A pinion 76 meshes with the gear 71.

The pinion 76 is keyed on a shaft 77, which has a gear 78 keyed thereto, said gear 78 meshing with a gear 79 keyed on the shaft 80. Thus the gears 78 and 79 and the shafts 77 and 80 will be rotating in opposite directions. Each of said shafts 77 and 80 has a gear 70 keyed thereon and between each of said gears 70, and the other gears 70 of the corresponding row of said gears is an idler gear 81. Thus all of the gears 70 of one row or line of gears rotate in the same direction and the other set of gears of the row opposite thereto rotate in the opposite direction. Thus the paired rollers 66 that are opposite each other are rotated in opposite directions, said direction of rotation being such as to feed the string of balls from left to right as viewed in Fig. 1.

The diameter of the rollers 66 is preferably substantially that of the ball formations or slightly smaller than the size of the ball formations. In the embodiment shown, the rollers 66 are of smaller diameter than-the ball formations. Also it is desirable that said rollers 66 engage the ball formations as closely together as possible. For this reason the rollers are made extremely long and the drive therefor is mounted at a considerable distance from their .point of engagement with ball for :mations, to thus permit the rollers to be crowded slightly out of parallelism so as to bring the same as close together as possible at their point of engagement with the ball formations. This can be accomplished because the gear teeth in the gears 70 and 81 mesh loosely enough to permit such slight movement out of line of the rollers, this movement being only slightly angularly at a great distance fromengagement with the ball formations.

In order to provide for a firm yielding grip of the ball formations by means of the rollers 66 the lower ends of the rollers are mounted in bearing blocks 82 slidably mounted in engagement with each other and in housing 'members. 83 mounted on a base 84 secured in any suitable manner, as by means of the angle members 85 on compression coil springs 88 mounted in corresponding socket portions 89 in the housings 83. Thus the rollers 66 will be yieldingly urged toward each other under the influence of the springs 88. The lower ends of the rollers 66 rest on the base 84 and a guide bar 90 is provided on said base 84, said guide bar 90 being located between the rollers 66 and thus limiting movement of the rollers toward each other. The guide bar 90 is accordingly of a width that is considerably less than the diameter of the connected ball formations. The rollers 66 thus all cooperate to prevent any twisting of the ball formations and will urge the same continuously toward the right, as viewed in Fig. 1, so that the connected ball formations will be fed properly into thetwisting rolls 24, 25 and 27.

The engagement of the rollers 66 with the connected ball formations is diagrammatically illustrated in Fig. 7, the direction of rotation of the rollers being indicated by the arrows thereon, and the direction in which the connected ball formations are being fed to the twisting rolls being indicated by the arrow on said series of connected ball formations, the ball formations being indicated by the numeral 91 in Fig. 7 and the narrow neck portions connecting the same by the numeral 92, it being, of

course, understood that the ball formations extend in connected relation continuously from the forming rolls 12 to those shown in Fig.7. The ball formation 91 shown at the right of Fig. 7 is being gripped by the pair of rollers 66 that are shown at the right of Fig. 7 so as to be held against rotation and is also being urged toward the right by said rollers, which are closely adjacent the entrance end of the twisting rolls 24, 25 and 27. The next ball formation 91 to the right of that shown in Fig. 7 is already in engagement with the twisting rolls 24, 25 and 27 and being rotated thereby. Thus as said rotation continues the ball formation in engagement with said twisting rolls will be twisted off from the ball formation 91 adjacent thereto, but the ball formation 91 that is still in engagement with the pair of rollers 66 at the right of Fig. 7 is being fed into position to be received in the grooves between the rolls 24, 25 and 27 and is thus fed into engagement therewith so as to be next rotated and twisted off from the ball formation next adjacent thereto at the left of said ball formation engaging said twisting rolls. This operation is repeated as the ball formations are fed to the twisting rolls. Thus each ball formation is separated from the other ball formations and upon reaching the discharge end of the twisting rolls so as to be disengaged thereby will drop out of the machine, suitable guiding means to direct said ball formations away from the driving mechanism and out of the machine being provided as may be desired.

In the operation of the machine the ball formations are formed of substantially the shape shown in Fig. 7 of the drawings by suitable forming or swaging rolls, of which the pair 12 is shown in the drawings. The forming mechanism discharges the connected ball formations and moves these toward the feed rollers 66, whereupon the connected ball formations are fed toward the twisting mechanism by the rollers 66 and also held against rotation about the axis of the connected string or series of ball formations thereby, said rollers 66 thus feeding and holding said ball formations against twisting about the axis "of the string or'series. Said ball formations are fed by .ball formation from the string or connected series.

Should for, any reason any ball formation 91 not be properly formed, or should any other obstacle enter between the rolls 24, 25 and 27, or should the ball formations not be fed by the rollers 66 in the proper relation into the entrance ends of the spiral grooves in the twisting rolls the yielding mounting of the roll 27 will permit it to move upwardly momentarily to relieve the rolls 24, 25

- and 27 and thus prevent any damage thereto by any improperly fed or mal-formed ball formations entering between the grooved rolls, the roll 27 being restored to the normal position by the spring 52 when such obstacle has passed from between the rolls 24, 25 and 27.

WhatIclaim is:

1. In a ball forming machine, ball separating means comprising a pair of twisting rolls mounted to rotate about fixed axes, a twisting roll cooperating therewith, means for yieldingly urging said cooperating roll toward said pair of rolls, means for positively rotating all said rolls continuously in the same direction, and means for continuously feeding connected ball formations to said twisting rolls.

2. In a ball forming machine, ball separating means comprising a pair of spirally grooved twisting rolls mounted to rotate about fixed parallel axes, a spirally grooved twisting roll mounted to rotate about an axis parallel to said axes cooperating therewith, resilient means for yieldingly urging said cooperating roll toward said pair of rolls, and means for continuously feeding connected ball formations to said twisting rolls in a direction parallel to the axes of said rolls.

3. In a ball forming machine, ball separating means comprising a pair of twisting rolls mounted to rotate about fixed axes, a twisting roll cooperating therewith, resilient means for yieldingly urging said cooperating roll toward said pair of rolls, and means for feeding connected ball formations to said twisting rolls comprising a plurality of pairs of closely spaced cylindrical rollers engaging said connected ball formations to hold said ball formations against rotation and means for continuously rotating said rollers at the same rate.

4. In a ball forming machine, ball separating means comprising a pair of spirally grooved twisting rolls mounted to rotate about fixed parallel axes, a spirally grooved twisting roll mounted to rotate about an axis parallel to said axes cooperating therewith, resilient means for yieldingly urging said cooperating roll toward said pair of rolls, means for positively rotating all said rolls continuously in the same direction, and means for continuously feeding connected ball formations to said twisting rolls in a direction parallel to the axes of said rolls comprising a plurality of rollers mounted to rotate about axes transverse to the direction of feed engaging said connected ball formations to hold said ball formations against rotation and means for continuously rotating said rollers.

5. In a ball forming machine, ball separating means comprising a pair of twisting rolls mounted to rotate about fixed axes, a twisting roll cooperating therewith, means for yieldingly urging said cooperating roll toward said pair of rolls, means for positively driving all of said rolls to rotate at the same rate in the same direction, and means for feeding connected ball formations to said twisting rolls.

6. In a ball forming machine, ball separating means comprising a pair of twisting rolls mounted to rotate about fixed axes, a twisting roll cooperating therewith, an arm upon which said cooperating roll is mounted, means for mounting said arm to swing about an axis parallelto that of one of said pair of rolls, resilient means for yieldingly urging said arm toward said pair of rolls and means for feeding connected ball formations to said twisting rolls.

7. In a ball forming machine, ball separating means comprising a pair of twisting rolls mounted to rotate about fixed axes, a twisting roll cooperating therewith, an "arm upon which said cooperating roll is mounted, means for mounting said arm to swing about an axis parallel to that of one of said pair of rolls and means for continuously positively driving all of said rolls to rotate at the same rate in the same direction including a gear rotating about the axis about which said arm is mounted to swing, and means for feeding connected ball formations -;to said twisting rolls.

8. In a ball forming machine, ball separating means comprising a pair of spirally grooved twisting rolls mounted to rotate about fixed parallel axes, a spirally grooved twisting roll mounted to rotate about an axis parallel to saidaxes cooperating therewith, an arm upon which said cooperating roll is mounted, means for mounting said arm to swing about an axis parallel to that of one of said pair of rolls, resilient means for yieldingly urging said arm toward said pair of rolls, means for continuously positively driving all said rolls including a gear rotating about the axis about which said arm is mounted to swing and means for feeding connected ball formations to said twisting rolls.

9. In a ball forming machine, ball separating mechanism comprising a plurality of twisting rolls and means for feeding connected ball formations to said twisting rolls comprising two transversely spaced rows of closely spaced cylindrical rollers, each of said rollers being of much greater length than diameter, the rollers of one of said rows being each opposite a roller of the other of said rows, means for suspending each of said rollers from its upper end portion with its axis extending in a generally vertical direction, means at the upper ends of said rollers adjacent said suspending means for positively driving the rollers of one of said rows in one direction and the rollers of the other of said rows in the opposite direction, said driving means rotating all said rollers continuously at the same speed, and a bearing member engaging each of the rollers of each of said rows adjacent its lower end, each of said bearing members being mounted for independent movement transversely of said rows of rollers, independently acting resilient means engaging each of said bearing members to urge the bearing member of each roller independently toward the roller opposite the same and means for limiting the movement of each roller toward the roller pposite the same.

10. In a ball forming machine, ball separating mechanism comprising a plurality of twisting rolls and means for feeding connected ball formations to said twisting rolls comprising two transversely spaced rows of closely spaced cylindrical rollers, the rollers of one row being more widely spaced from the rollers of the other row than the rollers of each of said rows are spaced from each other, each of said rollers being of much greater length than diameter, the rollers of one of said rows being each opposite a roller of the other of said rows, means for suspending each of said rollers from its upper end portion with its axis extending in a generally vertical direction, means at the upper ends of said rollers adjacent said suspending means for positively driving the rollers of one of said rows in one direction and the rollers of the other of said rows in the opposite direction, said the same and means for limiting the movement of each roller toward the roller opposite the same.

11. In a ball forming machine, ball separating mechanism comprising a plurality of twisting rolls and means for feeding connected ball formations to said twisting rolls comprising two transversely spaced rows of closely spaced cylindrical rollers, each of said rollers being of much greater length than diameter, the rollers of one of said rows being each opposite a roller of the other of said rows, means for suspending each of said rollers from its upper end portion with its axis extending in a generally vertical direction, means at the upper ends of said rollers adjacent said suspending means for positively driving the rollers of one of said rows in one direction and the rollers of the other of said rows in the opposite direction, said driving means rotating all said rollers continuously at the same speed, and a bearing member engaging each ot the rollers of each of said rows adjacent its lower end, each of said bearing members being mounted for independent movement transversely of said rows of rollers, independently acting resilient means engaging each of said bearing members to urge the bearing member of each roller independently toward the roller opposite the same, a guide member adjacent the lower ends of said rollers between said rows engaged by said rollers to limit the movement of each roller toward the roller opposite the same.

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